At a glance, looks pretty good and very clean, nice work!
The only thing that really stands out to me is the girl's face, which looks a little goofy to me. i think there are two factors at play:
1.) I think the facial features are squished together too much vertically. The mouth is too close to the eyes because the nose is seemingly missing (and the mouth was moved up to compensate?). Really, the top lip would start at a similar position as the male's closed smile, and the bottom would move downwards with the jaw following, with the nose in the same place as noses typically go.
2.) The perspective on her facial features don't follow the perspective of the face. Besides being too high on the face, the mouth looks about right, but the eyes should rotate to the right some so that they're actually on the front of the face. Currently the one closer to the camera is actually where her cheek would be. This is actually the case with the man as well, but it's less apparent I think, since everything else is in the right place (nose, mouth).
Overall it's pretty good though! The level of polish with the coloring is really nice, and the things I mentioned above are technical nit picks that the average reader won't notice or linger on too much.